Integrated circuits are tested for their functionality by the semiconductor manufacturer. This is also true in particular of computer cores, which must be tested for their functionality for safety reasons. This is done in the uninstalled state after manufacturing a microprocessor on a semiconductor chip at the semiconductor manufacturer's, where the computer core has not yet been installed in a control unit.
German Patent Application No. DE 10 2006 014 267 A1 describes a method for testing at least one processor installed in a control unit, in which test data are loaded via a control unit interface for testing a first processor, and then the first test data loaded are stored in the memory unit of the second processor. The first processor is then switched by the second processor to a test mode, in which the first test data are used. The test results of the first processor are checked for plausibility by the second processor.
However, only a certain degree of error recognition is ensured by these tests because such a test is allowed to block a processor only for a short period of time. Since the processor must be available again without restrictions immediately after the test, the test patterns that may be used and thus the error coverage are limited.